Temperature responsive device



Jan. 2, 1968 J. ALBERANI 3,361,349

TEMPERATURE RESPONSIVE DEVICE Original Filed Dec. 11, .1964

JUL /,US A: EE/PA/V/ INVENTOR BQOIEQTMW OQ.

ATTORNEY United States Patent 3,361,349 TEMPERATURE RESPONSIVE DEVICE Julius Alherani, 1695 Stanley, Birmingham, Mich. 48009 Continuation of application Ser. No. 417,602, Dec. 11, 1964. This application Dec. 16, 1966, Ser. No. 602,427 5 Claims. (Cl. 236-87) This application is a continuation of Ser. No. 417,602, filed Dec. 11, 1964.

This invention relates generally to temperature responsive devices, and more particularly to mechanically actuated, hydraulic signal type temperature responsive devices.

In the past, mechanical temperature responsive mechanisms have responded relatively slowly, in most instances requiring ten or more seconds to react. Also, these prior art mechanisms were generally designed in such a way that most of the structure thereof extended into the chamher or passage wherein the temperature was to be sensed. In those applications wherein it is necessary for air to flow through a passage, such as through the compressor of a gas turbine engine, such a bulky obstruction materially disrupts the air flow therethrough.

Accordingly, a primary object of the invention is to provide a novel temperature responsive device which takes up very little space within the passage wherein temperature is to be sensed, thereby eliminating objectionable obstructions to the flow therethrough.

A further object of the invention is to provide such a device which is capable of an extremely fast response to temperature changes, say on the order of one second, as compared to ten or more seconds in the case of prior art devices.

A still further object of the invention is to provide such a device which operates as a closed-loop force balance system, utilizing a null type servo.

Still another object of the invention is to provide such a device which is simple in construction and inexpensive to manufacture.

Other objects and advantages of the invention will become more apparent when reference is made to the drawing which is a cross-sectional view of a device embodying the invention, as applied to a typical housing.

Referring now to the drawing in greater detail, the temperature responsive device includes body portions 12 and 14 fastened together by any suitable means. The body portion 14 extends through an opening in a housing, represented generally by 16, such as the wall of a gas turbine engine compressor (not shown).

Openings 18 and 20 formed in the body portion 14 provide access of the surrounding air to the interior thereof, hereinafter referred to as chamber 22. A bimetallic disk 24 is confined within the chamber 22 against an upper wall 26. A stem 28 secured to the bimetallic disk 24 by any suitable means, such as a nut 30, extends through an opening 32 formed in the body portion 12 into an inner chamber 34. A suitable seal 36, surrounding the stem 32, prevents leakage between the chambers 22 and 34.

The piston 38 is fixedly secured to the stem 28. The specific securing means may consist of a threaded end 40 and members 42 and 44 tightened against opposiing faces of the piston 38, but is not limited to such an arrangement. As illustrated, the member 44 serves as a valve member in a manner to be described. A resilient means, such as a spring 46, is confined within the chamber 34 between the piston 38 and a fixed retainer ring 48.

The piston 38 forms a movable wall between the chamber 34 and a chamber formed within the body 12. An inlet 52 communicates between the chamber 50 and a source of high pressure fluid, represented generally by 54. For purposes of the invention, the high pressure fluid 3,351,349 Patented Jan. 2, 1968 may be either regulated, as by a constant pressure diflerential valve, or nonregulated, as the variable output from a centrifugal pump or from a speed sensor.

A member 56 is threadedly inserted through an opening 58 in the body 12 into the chamber 50. leakage therepast may be prevented by means of seals 59. An annulus 60 is formed around the member 56 intermediate the ends thereof. An axial passageway 62 and transverse passageways 64 intersect to communicate between the chamber 50 and the annulus 60. A servo valve seat 66 is inserted into a counterhored opening formed around the axial passageway 62, and a passage 68 is formed through the seat 66 and aligned with the axial passage 62. The location of the servo valve seat 66, and hence the pressure differential resulting from a given temperature change, may be manually adjusted by inserting a suitable tool in the hexagonal opening '70 formed in the outer end of the member 56, and rotating the same.

Passages 72 and 74 communicate between the annulus 60 and the chamber 34. An outlet 76 serves to communicate the fluid flow from the annulus 60 to a conduit 78 leading to any device 80 wherein the hydraulic tempera ture signal may be utilized, such as a fuel control device wherein it may be desired that a metering valve be con trolled as a function of the temperature in a selected compressor stage.

A conduit 82, including a restriction 84, communicates between the conduit 78 and the inlet side of the source 54 of high pressure fluid in order to complete the flowing system.

Operation As explained above, the housing 14 is secured to a body 16, such as the inlet to the compressor of a gas turbine engine, in which the temperature is to be sensed. The bimetallic disk 24 will, therefore, be directly influenced by the temperature of the air passing therethrough. In response to changes in the compressor inlet air temperature, the confined bimetallic disk 24, being secured to the stem 28, will create an axial force on the piston 38. The piston 38 reacts against the null type servo opening 44/68. By null type servo is meant that the actual movement of the element 44 toward and away from the opening of the passage 68 is extremely small, say on the order of .005 to .010", throughout the over-all operating range of the system. This range may be varied by changing the size of the fixed restriction 84.

The upper edges of the disk 24 must remain in contact with the upper wall 26 of the body portion 14 at all times. This is accomplished by virtue of the relaxed free overall length of the assembly, comprising the disk 24, the stem 23 and the member 44, being greater than the distance between the opening of the passage 68 and the upper wall 26. In other words, the components involved are assembled under tension. Some 50 drop below the predetermined minimum operating temperature would have to occur before the disk assembly could become completely free within its confines. Once the system has been put into operation, the high pressure in the chamber 50 from the source 54 will immediately lift the member 44 oil the seat 66 to a position within the above mentioned .005" to .010" range.

Now, for the sake of illustration, let it first be assumed that inlet air temperature increases. Since the disk 24 is formed so as to dish further with increasing temperature, the piston 38 will immediately be forced downwardly, tending to close off the servo opening 44/68, thereby reducing fluid flow through the opening and causing the downstream pressure T to decrease. The immediate result is an increase in the pressure differential across the piston 38 due to the closed-loop type force balance system, wherein the pressure T in the annulus 60 is communicated to the chamber 34 via, the passages 72 and 74. This causes the piston 38 to react to oppose the downward movement caused by the disk 24, until the progressively increasing pressure differential balances the combined downward force of the spring 46 and the bimetallic disk 24. The spring 46, being a substantially constant load spring to the null system, merely sets a minimum pressure diiferential across the piston 38. At this point, the system is once again in equilibrium and the device 80 is receiving a new hydraulic signal, via the conduit 78, which is a function of the temperature within the housing 16.

Should the compressor inlet air temperature decrease, the instantaneous reaction of the bimetallic disc 24 would be to relax slightly, although still remaining abutted against the upper wall 26. This would permit the high pressure within the chamber 50 to force the piston 38 upwardly in the illustration, further away from the opening of the passageway 68. This slight opening of the servo opening 44/68 permits a greater fluid fiow through the opening, thus increasing the pressure T in the chamber 34, via the passages 62, 64, 72 and 74. The resultant progressively decreasing pressure difierential across the piston 38 reacts to oppose the upward movement until such time as the differential thereacross balances the lessened downward'total force of the bimetallic disk 24 and the spring 46.

It is apparent that the pressure T received by the device 80 is a function of the temperature of the air at the inlet of the compressor. This temperature signal is at all times communicated to the device 80 via the outlet 76 and the conduit 78.

It should be apparent that the closed-loop mechanically actuated temperature responsive device may be used in any application wherein a slave member or other mechanism, such as a piston within any device 80, must be operated in response to changes in temperature of a selected atmosphere.

It should also be apparent that the device may be employed in any fluid media.

While but one embodiment of the invention has been described and discussed, it is apparent that other modifications of the invention are possible within the scope of the appended claims.

What I claim as my invention is:

1. A null-type, closed-loop, hydromechanical, position feedback device adapted for flowing circuit connection between a source of hydraulic pressure and a hydraulic signal-utilizing mechanism to convert a hydraulic input pressure into a hydraulic output pressure signal proportional to the temperature to which said device is subjected, said device comprising a body formed to provide a hydraulic pressure inlet, a hydraulic pressure signal outlet, a passageway communicating said inlet and outlet, valve seat in said passageway, a movable pressure responsive element in said passageway and having a valve at the side thereof adjacent said valve seat, an exposed temperature responsive element at one end of said body, a solid connection between said temperature responsive element and said pressure responsive element, and a passageway communicating pressure downstream of said valve seat to the side of said pressure responsive element opposite said valve seat, the pressure differential across said pressure responsive element being dependent upon the position of said valve with respect to said valve seat, whereby the instantaneous equilibrium position of said valve at any particular temperature is determined by a balance of the forces resulting from said pressure dilferential acting on said pressure responsive element to move said valve away from said seat and said temperature responsive element acting to move said valve toward said seat, resulting in the hydraulic pressure downstream of said valve seat always being a function of temperature only and independent of variations in the input pressure.

2. A device such as that recited in claim 1, wherein said valve seat is adjustable with respect to said valve.

3. A device such as that recited in claim 1, wherein said temperature responsive element is a bimetallic element.

4. A device such as that recited in claim 1, wherein a constant force spring means urges said pressure responsive element toward said valve seat, the combined forces of said constant force spring and said temperature responsive element acting to move said valve toward said seat.

5. A device such as that recited in claim 1, wherein said pressure responsive element is a piston.

References Cited UNITED STATES PATENTS 554,398 2/1896 Powers 23686 2,118,248 5/1938 Keinath 23684 2,199,730 5/1940 Piron 236-86 2,401,861 6/1946 Cunningham 236-87 2,946,509 7/1960 Radtke 236 87 2,979,952 4/1961 Eastman 236-87 X 3,212,711 10/1965 Karminski 23687 3,223,105 12/1965 Hogel 23686 X FOREIGN PATENTS 622,693 6/1961 Canada.

785,191 5/1935 France.

WILLIAM J. WYE, Primary Examiner, 

1. A NULL-TYPE, CLOSED-LOOP, HYDROMECHANICAL POSITION FEEDBACK DEVICE ADAPTED FOR FLOWING CIRCUIT CONNECTION BETWEEN A SOURCE OF HYDRAULIC PRESSURE AND A HYDRAULIC SIGNAL-UTILIZING MECHANISM TO CONVERT A HYDRAULIC INPUT PRESSURE INTO A HYDRAULIC OUTPUT PRESSURE SIGNAL PROPORTIONAL TO THE TEMPERATURE TO WHICH SAID DEVICE IS SUBJECTED, SAID DEVICE COMPRISING A BODY FORMED TO PROVIDE A HYDRAULIC PRESSURE INLET, A HYDRAULIC PRESSURE SIGNAL OUTLET, A PASSAGEWAY COMMUNICATING SAID INLET AND OUTLET, VALVE SEAT IN SAID PASSAGEWAY, A MOVABLE PRESSURE RESPONSIVE ELEMENT IN SAID PASSAGEWAY AND HAVING A VALVE AT THE SIDE THEREOF ADJACENT SAID VALVE SEAT, AN EXPOSED TEMPERATURE RESPONSIVE ELEMENT, AND ONE END OF SAID BODY, A SOLID CONNECTION BETWEEN SAID TEMPERATURE RESPONSIVE ELEMENT AND SAID PRESSURE RESPONSIVE ELEMENT, AND A PASSAGEWAY COMMUNICATING PRESSURE DOWNSTREAM OF SAID VALVE SEAT TO THE SIDE OF SAID PRESSURE RESPONSIVE ELEMENT OPPOSITE SAID VALVE SEAT, THE PRESSURE DIFFERENTIAL ACROSS SAID PRESSURE RESPONSIVE ELEMENT BEING DEPENDENT UPON THE POSITION OF SAID VALVE WITH RESPECT TO SAID VALVE SEAT, WHEREBY THE INSTANTANEOUS EQUILIBRIUM POSITION OF SAID VALVE AT ANY PARTICULAR TEMPERATURE IS DETERMINED BY A BALANCE OF THE FORCES RESULTING FROM SAID PRESSURE DIFFERENTIAL ACTING ON SAID PRESSURE RESPONSIVE ELEMENT TO MOVE SAID VALVE AWAY FROM SAID SEAT AND SAID TEMPERATURE RESPONSIVE ELEMENT ACTING TO MOVE SAID VALVE TOWARD SAID SEAT, RESULTAING IN THE HYDRAULIC PRESSURE DOWNSTREAM OF SAID VALVE SEAT ALWAYS BEING A FUNCTION OF TEMPERATURE ONLY AND INDEPENDENT OF VARIATIONS IN THE INPUT PRESSURE. 